AUSTIN (KXAN) — As ERCOT announced Thursday all controlled outages have ended in Texas, it also shed light on how close the state came to “catastrophic” blackouts.

With the end of controlled outages, utility companies, including Austin Energy, Oncor, and others, can bring back all power online as each utility sees fit.

ERCOT President and CEO Bill Magness said during a news conference Thursday the company authorized transmission operators at utilities to get power back to those affected by Monday’s mandated load shed outages. Those outages ended up being prolonged, not rotating like originally planned.

“There’s still a lot of work they have to do to get that to the customers,” Magness said. “Restoring the outages in the field is a process they have to take.”

Some people will remain without power for now due to this slow process. Others will be without power due to infrastructure problems caused by the ice and snow storms.

Magness said more generation came online Wednesday, and it was enough to support the demand without the prolonged forced outages in place.

ERCOT was able to get past Thursday morning’s power demand peak without having to ask utilities to decrease load, so that was encouraging, Magness said. He warned, however, that “we’re not out of the woods yet.”

“We’re still in very cold conditions, so we’re seeing much higher than normal winter demand, so we’re keeping a close eye on that,” Magness said. “We still expect a high cold-weather peak Friday, but we feel like we’re in a glide path.”

He said if ERCOT “hits a bump,” it may have to ask for outages, but it should actually be rotating and not nearly as long as the outages that began Monday.

Does ERCOT decide where the power goes out?

The short answer is no. Magness said utilities like Oncor or Austin Energy, as examples, have their own plans to figure out where they can shut power off. They said “critical” facilities like hospitals, fire stations, water treatment plants and so on are exempt from the blackouts, so it’s up to local utilities to reduce load. All ERCOT does is ask utilities to reduce a certain amount of load, and the local operators get there how they can.

“The one thing we have to ensure is that we don’t have a catastrophic blackout,” Magness said. “The reason we took this action (earlier this week) was to prevent that type of blackout.”

Dan Woodfin, the senior director of operations with ERCOT, said once generation went offline and energy supply dwindled, there’s not much “from a laws of physics perspective” the agency can do when demand is higher than supply.

“By our operators taking the actions they took, they preserved the integrity of the system,” Woodfin said. “As long as the outages have been, and as hard as they’ve been for folks, they’ve allowed us to transition back to where we are restoring power much quicker than we would have if this happened in an uncontrolled way.”

Magness said if they would have “let physics do the job,” they wouldn’t have been able to even hold the news conference they supplied all this information at.

“We wouldn’t be talking about restoration today or tomorrow — we would be telling you that we’re not sure when it would be done,” Magness said. “It would take much, much longer.”

How close was Texas to a ‘catastrophic’ blackout?

When asked how close the grid was from having a “catastrophic blackout,” Magness said if transmission operators hadn’t reacted “very rapidly to change the situation,” things could have escalated quickly.

“We were at a level of frequency that needed to be addressed immediately,” Magness said, “and that’s what the operators did. It was seconds and minutes, given the amount of generation coming off the system at the same time the demand was still going up significantly.”

Woodfin explained there’s a “safety net” that automatically takes effect if transmission operators aren’t able to reduce load fast enough. He said the system, called under-frequency load shed, will automatically shed a percentage of load if the frequency drops really far, really fast due to severe power supply imbalance.

“They’ll automatically shed 5%, and then if it drops further, it’ll shed 10%, and then if it gets worse, it’ll shed an additional 10%, Woodfin said. “If our operators and transmission owner operators can’t shed load in a controlled way, which is what we did, by choosing which circuits are taken out, it should protect us for 25% loss in generation.”

Woodfin simplified it by saying the laws of physics say the load has to match the generation, and he said doing it in a controlled way is much better than letting the safety net handle it.

How will this affect power bills?

Magness said ERCOT doesn’t have anything to do with customers’ power bills, so he couldn’t say if customers will see higher power bills.

“We aren’t in the retail energy business, so we really can’t speak to customer bills,” Magness said. “We work in the wholesale market and with the transmission system, so we really wouldn’t want to speculate on what individual customers could see.”

Woodfin said it will take months to put together a report of which generators went offline that necessitated the outages. He said they have computers that track when generators go offline and when they come back on, so he said it will probably be a “fairly massive” public report.

Before anyone compiles that report, however, they want to get power back on for everyone.

“We will be doing that once we get through the immediate problem, which is making sure we get everybody back and get the system working normal again,” Woodfin said.